Do you see POST screen when the system is powered on? If so then open your system cabinet and take out the graphics card from the slot and insert it to another PCI slot, then power on your system and see what happens. This might be the PCI slot or the display driver itself causing the problem. Windows will recognize the card from the new slot and there might be a chance to show the display. If that doesn't work then try to boot with Windows installation CD or DVD. If you see the setup screen then try to repair windows.
Please provide the result of the workaround.